CHAPTER THREE
MOTOR GRADER
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Outline
➢Introduction
➢Function of Motor Grader
➢Classification of Motor Grader
➢Main Component of Motor Grader
➢Motor Grader Preventive Maintenance
➢Specification of Motor Grader
➢Motor Grader productivity estimation
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INTRODUCTION
✓ The grader or motor grader is a machine used principally in
shaping and finishing.
✓ A grader consists of a wide, controllable blade (moldboard)
mounted at the center of a long-wheelbase.
✓ The blade is usually held at an angle to travel direction.
✓ It will cut, fill, and side cast. These functions can be performed
separately or at the same time, in any combination
✓ It is available in sizes ranging from 35 to over 600 horsepower,
in a variety of constructions.
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MOTOR GRADER FUNCTIONS
➢ Moving of earth from one location to another.
➢ Leveling of soil so that next bitumen layer spread uniformly throughout the
surface.
➢ Scarifying. Scarifying is the removal of complete layer of soil and then
spreading of a new layer at that particular location.
➢ Motor grader is a machine also used during :
➢ Gravel Road Repairing
➢ Road Shoulder Reshaping
➢ Bank Cutting
➢ Ditch Filling
➢ Base Course Spreading
➢ Snow , Land Clearance
➢ Frozen Top Soil, Asphalt Breaking
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CLASSIFICATION OF MOTOR GRADER
1.Rigid frame motor grader
2.Articulated frame motor grader
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Classification Of Motor Grader cont..
1.Rigid frame motor grader
✓ It requires space for turning and requires maximum side shift
to clean ditches unless the grader can get into the ditch.
✓ It is best on a stable work platform.
✓ It is good for smooth blading
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Classification Of Motor Grader cont..
2.Articulated frame motor grader
✓ It can be turned and maneuvered in tighter spaces.
✓ The frame allows offsetting the drive wheels away from edges
and ditches.
✓ Offsetting puts the most machine power and mass directly
behind the load on the moldboard while keeping side-shift to a
minimum to reduce strain on the circle.
✓ When properly used it is a good choice for the heaviest work
and work near edges
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MAJOR COMPONENTS OF MOTOR GRADER
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Major Components
➢ Mold board ➢ Operators cab
➢ Circle assembly ➢ Prime mover (engine)
➢ Draw bar ➢ Tandem drive
➢ Sacrifier/Ripper ➢ Frame
➢ Controls
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Moldboard/blade
✓ The moldboard also called blade is the graders working tool.
✓ Generally 12 or 14 feet in length the mold board consists of a
bolted-on cutting edge and end bits.
✓ The cutting edge is attached to bottom of the moldboard while
the end bits are attached to each side.
✓ They act as wear plates protecting the moldboard and must be
replaced or reversed when worn or broken.
✓ In most cases the bolts will also have to be replaced
✓ The position and pitch of the moldboard can be hydraulically
manipulated
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Moldboard/blade
POSITION POSSIBILITIES
1. Lift and lower right
2. Lift and lower left
3. Moulboard frame sideshift
4. Mouldboard sideshift
5. Rotating angle
6. Pitch Cutting angle
Pitch Cutting angle
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✓ When the moldboard is angled to the direction of travel the
terms heel (trailing edge of blade) and toe (leading edge of
blade) are used to identify the ends of the moldboard.
✓ The moldboard can be rotated 3600 in either direction.
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Circle assembly
➢ The circle is a tooth ring gear that is rotated in a
supporting frame by the circle reverse
mechanism.
➢ Depending on the make and model of the grader,
the circle teeth may be internal or external.
➢ The circle is turned by a spur pinion gear teeth
that mesh with the circle teeth.
➢ The spur pinion gear is held by the draw bar and
controlled by a lever in the operators cab
➢ By engaging the spur pinion gear, the circle and
mold board can rotate 360 degrees in either
direction.
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Draw bar
➢ The draw bar is a V or T shaped connection between the
front of the grader frame and the circle.
➢ The draw bar holds the circle rigid and fastened by a ball
and socket that allows angular movement from side to side
and up and down.
➢ The draw bar carries the full horizontal load on the mold.
➢ Other components provide vertical and side support
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Scarifier/ripper
➢ The scarified is a set of teeth used for breaking up surfaces too
hard to be readily penetrated by the blade.
➢ A ripper attachment is a claw like device used for breaking up
asphalt, large rocks and tree stumps.
➢ is usually raised and lowered by a hydraulic cylinder.
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Prime mover
✓ Most construction equipment is powered by internal
combustion engines.
✓ Diesel engines perform better under heavy duty applications
than gasoline engines.
✓ Diesel powered machines are the work horses of the
construction industry.
✓ The prime mover is a rubber tired tractor, powered by a 6 to 12
cylinder diesel engine mounted at the rear over the driving
wheels for increased traction.
✓ The prime mover has four rear mounted single tires driven in
tandem drive through gears and chains and a single steering
axle
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Tandem drive
➢ The graders tandem dive allows climbing over
rocks, logs, or humps and permits passing through
depressions and ditches one wheel at a time.
➢ When one rear wheels raise or lower, while the
other remains on the same level with the front
wheel, thereby holding the grader on a level
terrain.
➢ Depending on the specific operation, the end
result is an even cut, spread, or uniform side cast.
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Frame
➢The frame connected to the front axle extends
the full length of the graders and is high enough
to allow space for carrying and manipulating
the working tools.
➢The front axle is compound.
➢The lower section carries the weight of the
graders oscillate on the center pin and is hinged
to the bottom of the spindle.
➢The upper section of the axle is hinged to the
top of the spindle, allowing the front wheels to
lean left or right, as well as turn.
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Controls
✓ Grader operations involve using levers located on the left and
right side of the steering wheel.
✓ The caterpillar 135H grader has a total of nine levers as shown
below.
✓ Stamped with their individual function most of these levers
have three positions, forward, center, and back.
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Blade lift controls for the left and right
✓ The blade lift controls raise and lower the left or right end
of the blade.
Blade side shift lever
✓ The blade side shift lever moves the blade left or right
Blade circle drive lever
✓ The blade circle drive lever rotates the circle clockwise or
counterclockwise
Blade tip control lever
✓ The blade tip control lever tilts the top of blade forward or
back.
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Articulation control
✓ The articulation control moves the rear of the grader left or
right.
Center shift control
✓ The center shift control moves the drawbar left or right.
Wheel lean control
✓ The wheel lean control tilts the wheels left or right
Ripper/scarifier
✓ The ripper/scarifier lever raises and lowers the ripper or
scarifier.
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Motor Grader Preventive Maintenance schedule
M a c h in er y preventive maintenance schedule & checklist
M a ch in e type … … … … … … … … … … … … … … Date …… …………………… … … … . . . . . . . . . . . . . . .
Plate no. … … … … … … … … … … … … … … … . . . . Location …….....................................................
Manuf. & model … … … … … … … … … … … … … Mech. N a m e & sig. …………………...............
Last service Current time reading N ext service
Date . . . … … … … … … . . . . … … … … … … … … . . … … … … … … … …
Hr./Km. … … … … … … … . . . … . … … … … … … … … . .……………...........
SER V IC E S TA G E … … … … … … … . T O T A L C O S T … … … … … … … … … … . .
Service stage A B C D E F G H I J
Service hour 250 500 750 1000 1250 1500 1750 2000 2250 2500
Pre-start check ,change , repair points Service check change repair remark
interval
ENGINE Oil & filter 250hr
F u e l filter 500hr
Coolant & Radiator cap check ,change as needed 250hr
Belt & belt tensioner check clean & adjust 1,000hr
Engine m o u n t i n g security 500hr
Air cleaner change 1,000hr
Exhaust leakage check 250hr
HYDRAULIC Oil level c h e c k & sampling 250hr
SYSTEM System leak 250hr
S y s t e m oil filters 1,000hr
Oil & oil c o o l e r c h e c k & c l e a n 2500hr
Hydraulic p u m p m o t o r & transmission security 500hr
OTH ERS C h e c k lighting ,starting & c ha rging 1,000hr
Battery terminal condition 250hr
Battery electrolyte level & proportion 250hr
C hec k & c ha nge air drier 1,000hr
C h e c k & a d j u s t b r a k e s h o e c h a n g e if n e c e s s a r y 500hr
Security of major m o u n t i n g bolts 2,000hr
G e a r b o x & di f f erent ia l s t a t us & oil 1,000hr
L u b r i c a t e all h i n g e s & g r e a s i n g all pivot p i n s 250hr
Dismantle, check & lubricate steering & h u b device 1,000hr
Dismantle, check &lubricate axle, h u b device 1,000hr
S/ C h a n g e d spare part unit QT Unit Total Mechanic Labor Time Total
N & oils Y price price name cost/hr. taken hr. cost
1
2
3
4
5
6
7
Tot a l s p a r e & oil p r i ce Total labour cost
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SPECIFICATION OF MOTOR GRADER
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Specification Of Motor Grader cont.…
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Specification Of Motor Grader cont.…
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Specification Of Motor Grader cont.…
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MOTOR GRADER PRODUCTION
ESTIMATION
➢ Productivity is the ratio of useful work out put to the time spent
to complete that work.
➢ There are many ways to measure motor grader operating capacity,
or production.
➢ One method expresses a motor grader’s production in relation
to the area covered by the moldboard.
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Motor Grader Production Estimation cont.…
➢ Where :
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Motor Grader Production Estimation cont.…
Operating speed Cont…
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Motor Grader Production Estimation cont.…
➢ Where :
Effective Blade Length:
➢ Since the Moldboard is usually angled when moving material, an effective blade length must be
computed to account for this angle. This is the actual width of material swept by the Moldboard.
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Motor Grader Production Estimation cont.…
➢Effective Blade Length cont.…
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Motor Grader Production Estimation cont.…
Where:
Width of Overlap:
➢ The width of overlap is generally 0.6 m (2.0 ft).
➢ This overlap accounts for the need to keep the tires out of the
windrow on the return pass.
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Motor Grader Production Estimation cont.…
Where
Job Efficiency:
➢Job efficiencies vary based on job conditions,
operator skill, etc. good estimation for
efficiency is approximately 0.70 to 0.9
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Motor Grader Production Estimation cont.…
❑TIME ESTIMATES
Total Time = P x D
SxE
P = number of passes required
D = Distance in km/ pass
E = Grader efficiency
S = Speed of grader
Total time = hours required to complete a grader operation
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Example #1
A 14H motor grader with a 3.66 m moldboard is
performing road maintenance on a township road
with operating efficiency of 0.9. The machine is
working at an average speed of 7.1 km/h with a
Moldboard carry angle of 30 degrees. What is the
motor grader’s production based on coverage
area?
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Thank you
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